Effects Of Transgenic Bt Corn On Soil Animal Community Structure

With the constant development of transgenetic technology, GM corn industry with product characters like insect resistance and herbicide resistance has received a breakthrough. Anti-insect corn with Bt gene modified is the fastest commercialized GM corn with insect resistance. The crystal protein gene was transferred from the Bacillus thuringiensis(Bt) into this corn, and made it able to produce anti-insect protein, which had a ideal control on target insects. While GM corn industry with Bt gene develops globally, its safety has drawn concerns. How GM corns affect soil eco-system has become a hot research for us to assess the risk within. Based on the major producing area of spring corn and its typical black soil environment, this study starts with field plant situ investigation on root-zone and simulation of controlled litter decomposition, and investigates the influence Bt gene modified corns have on its soil animal community through two different scales. The field situ investigation chooses two different GM corns(Bt-799 and IE09S034) and their own contrastive non-GM corns; the simulation experiment on control of residue degradation chooses one GM corn(Bt-799), its contrastive non-GM corn(Zheng 58) and the local major corn(Zheng dan 958). This study researches the influence Bt GM corn’s plantation and its residue degradation have on its soil animal community, and looking forward to the scientific data for the ecosystem safety assessment of Bt GM corns and its degradation products. The flowing are research results:With corns have our nation’s intellectual property rights: the anti-insect corn Bt-799 with cry1 Ac gene modified and its contrastive Zheng 58, anti-insect corn IE09S034 with cry1 Ie gene modified and its contrastive Zong 31, this research uses hand-picking, pitfall traps method and Macfadyen method, and checkes the animal’s structure, composition and dominant species’ dynamics as parameters, to study the influence GM corn Bt-799 and IE09S034 have on the diversity of its soil animal community. Results show, through methods of hand-picking, pitfall traps and soil funnel, by comparing the animal community’s parameters of GM corn Bt-799 with Zheng-58, like its composition, richness, Simpson dominant index, Shannon-Wiener diversity index, Pielou evenness index and dominant species’ dynamics, etc, we can conclude that the GM corn Bt-799 has no significant effect in all periods. By comparing GM corn IE09S034 with non-GM corn Zong 31, only in soil animal community investigation between GM and non-GM corn through hand-picking method we found significant difference in amount of lepidopteran larvae. This is because it’s the target insect of anti-insect corn IE09S034 with cry1 Ie gene modified, and it caused the significant difference in GM corn and non-GM corn’s lepidopteran larvae number, other number of other groups has no significant difference between GM and non-GM corns. During the soil funnel investigation on GM and non-GM corn’s influence on dominant species in soil, the dominant species springtail’s number came with a significant difference in September’s sample. In addition, other investigation methods in different periods, comparing the GM corn IE09S034 with Zong 31, there is no significant difference in parameters like field animal group’s species richness, Shannon-Wiener diversity index, Pielou evenness index and dominant species’ group dynamics. The Bt-799 and IE09S034 of GM corn could be preliminarily identified to have no safety risk to the soil animals in the field, and neither any new born safety risk.This study chooses three experiment materials: cry1 Ac gene modified anti-insect corn Bt-799 and its non-GM contrastive species Zheng-58, conventional local species Zheng dan-958, to pick their withered leaves and study the influence GM corn Bt-799 has on its soil animal group through method of residue degradation bags. The result of study indicates that the GM corn Bt-799 compared to the corresponding non-GM control Zheng 58, the richness of soil animal groups, enrichment, Pielou evenness index, Simpson dominance index, Shannon Wiener diversity index and richness of dominant groups(Acarina, Collembola) are not significantly affected. The local major conventional species: Zheng Shan-958 has significant difference with Bt-799 and its control Zheng-58 only in soil animal group richness and abundance. Other characteristics parameters of the community have no significant difference. The difference of soil animals between conventional local species Zheng dan-958, GM corn Bt-799 and contrastive Zheng 58 isn’t caused by genetic modification. The GM corn Bt-799’s leaf residue degradation could be preliminarily identified to have no safety risk to structure of soil animals in the field.